1. Field of the Invention
The present invention relates to a microscope lens barrel including an input port where observation light enters the microscope lens barrel, a plurality of output ports where the observation light goes out of the microscope lens barrel, and an optical-path switching mechanism which selectively switches the optical path of the observation light to guide the observation light from the input port to at least one of the output ports.
2. Description of the Related Art
One conventional microscope lens barrel is a trinocular lens barrel switchable between visual and camera observation (see Japanese Patent Application Laid-Open No. H8-114749 and Japanese Patent Application Laid-Open No. 2005-221560). The main body of such a trinocular lens barrel, which is mounted on a microscope main body, generally includes an input port where observation light enters the lens barrel from an objective lens, an imaging lens which converges the entering observation light to form an observation image, a plurality of output ports where the observation light goes out to a binocular unit used for visual observation or a camera used for image observation, and an optical-path switching mechanism which selectively guides the observation light to at least one of the plurality of output ports. The binocular unit and the camera are attached to the lens barrel main body a neighboring parts of the corresponding output ports to be optically connected to the output ports, respectively. The imaging lens is provided in the input port or around the gate area of the input port.
On the other hand, a recent expansion in application of microscopes increases a demand for providing various measuring devices except for the camera on the trinocular lens barrel to observe a sample. Accordingly, there rises a necessity of mounting the measuring device heavier than the conventional camera on the lens barrel main body. In this case, larger load than ever is applied on the lens barrel main body, and thus greater strain is caused in the lens barrel main body and in optical elements provided therein. Therefore, there is a possibility of causing not only degradation in the quality of observation images but also a failure in obtaining desired observation accuracy. Moreover, since the load imposed on the microscope main body is accordingly increased, there is a possibility that the degradation in the image quality and the reduction in the observation accuracy are further aggravated.